1. Field
The present disclosure relates generally to monuments used by metrology systems and, in particular, to monuments that are mounted on robots. Still more particularly, the present disclosure relates to a method and apparatus for tracking mobile reference points using a robotic-mounted monument system.
2. Background
Monuments may often be used in environments in which metrology systems are used. A metrology system may be any system configured to generate measurements for one or more parameters. Examples of metrology systems may include, but are not limited to, optical measuring systems, motion capture systems, laser tracking systems, imaging systems, radar systems, global positioning systems, thermal imaging systems, and other types of sensor systems.
As used herein, a “monument” for a metrology system may be a rigid structure that may be used as a reference point by the metrology system. A monument used for a metrology system may also be referred to as a metrology monument. Metrology monuments for a metrology system may need to be located such that there is a clear line-of-sight between the metrology monuments and the metrology system.
Typically, metrology monuments may be placed at fixed locations within the area in which the metrology system is to be used. The area may be, for example, without limitation, a manufacturing area, a testing area, an assembly area, or some other type of area. However, in some situations, the locations in which these metrology monuments are placed may limit the clear line of sight between the metrology monuments and the metrology system.
As one illustrative example, a flexible manufacturing environment may use automated guided vehicles (AGV's) to transport large aerospace structures along a factory assembly line. The automated guided vehicles may require that the surfaces on which these vehicles move be substantially flat, smooth, and free of obstructions. Consequently, within this type of environment, the potential locations at which metrology monuments may be placed may be limited to locations on the sides of the work area. These locations may not always provide the clear lines of sight needed between a metrology system and the metrology monuments.
Some currently available metrology monuments may be placed on mobile platforms such as, for example, without limitation, roll carts. These metrology monuments may then be manually rolled out into the work area when needed by a metrology system and manually rolled out of the work area when not needed by the metrology system. In this manner, the metrology system may be stored out of the way until needed.
However, manually moving the metrology monuments in and out of the work area may pose safety concerns for the workers moving the metrology monuments. In particular, work environments such as, for example, without limitation, highly automated factory environments, may present safety issues for workers. Therefore, it would be desirable to have a method and apparatus that take into account at least some of the issues discussed above, as well as other possible issues.